High energy electromagnetic energy beams such as those produced by lasers have been found to be very useful in performing a variety of medical procedures.
The most commonly used surgical lasers are argon lasers, neodymium in yttrium aluminum garnet (Nd-YAG) and carbon dioxide (CO.sub.2) lasers. Helium-neon, excimer, ruby lasers and a variety of other lasers have also been used to a lesser extent as surgical lasers. Each of these lasers generates light of different wavelengths, which in turn, interacts differently with different types of tissues. For example, an argon laser is absorbed well by pigmented tissue and is primarily used in ophthamology to coagulate tissue. One principal use is to fuse the retina back into place. An Nd-YAG laser penetrates more deeply than an argon laser and is principally used as a coagulator. It has been used effectively for gastroenterology for coagulating ulcers and lesions. The Nd-YAG works well for gastroenterology because its beam can be carried by a fiber deep inside the body to places which are relatively inaccessible by conventional surgical means.
The CO.sub.2 laser is essentially a surface device and does not penetrate very deeply into tissue. It is most effectively used as a cutter, because it can cut quickly through tissue layer by layer by applying large amounts of heat directly on the surface to vaporize the tissue. Very high power levels can be delivered by a CO.sub.2 laser and it can even be used to vaporize bone. CO.sub.2 lasers have been particulary effective in gynecology surgery, where they can be used to split open a fallopian tube or to remove adhesions from organs such as ovaries or fallopian tubes. Particularly in the gynecological environment, it is important to prevent the CO.sub.2 laser beam from traveling farther into the tissue than is necessary. In fallopian tube surgery, it is desirable to split the anterior surface of the fallopian tube without damaging the posterior surface. It would be very useful to have an instrument which could be inserted into the fallopian tube so that only one surface of the tube would be affected by the CO.sub.2 laser beam.
CO.sub.2 lasers are very good for removing adhesions which adhere to various organs. Sometimes adhesions will surround the fallopian tubes and the ovaries. If the ovary is otherwise in good condition, one would wish to shield the ovary and the surrounding organs and tissue from the CO.sub.2 beam while the adhesion is vaporized with the CO.sub.2 laser. Adhesions are usually made of connective tissue which can extend enormously around the adhesion site. One wishes to destroy the adhesion without damaging the surrounding vital organs.
Because of the uses to which an argon surgical laser is put, it is not often necessary to insert laser beam absorption tools into the surgical site. However, it is desirable to assure that surgical instruments used in the operating room environment will not reflect the laser beam so that it would be useful to have laser-absorbing coatings on the apparatus used in the vicinity of an argon laser.
Similarly, because of the uses to which an Nd-YAG surgical laser is put, specific laser beam absorbing tools are not generally used for the YAG laser. However, again, it is also useful to render surgical tools used in the vicinity of the surgical site laser beam absorbing rather than reflecting.
With CO.sub.2 surgical lasers, it is particularly useful to have instruments which are specifically designed to act as backstops and shields for laser beams to intercept the laser beam after it has been delivered to the surgical site and before it can energize surrounding tissue, organs or bone. It is also useful to render all of the surgical instruments that are used in the vicinity of the CO.sub.2 laser absorbing so that they will not reflect the CO.sub.2 beam onto healthy organs, tissue and bone.
In the past, attempts have been made to provide surgical tools which would absorb laser energy by, for example, changing the color of the surgical tool from its shiny, silvery stainless steel appearance to a dull black finish. Although this may be effective in some circumstances, physicians have found the problem of absorbing undesired laser beams significant enough to cause many physicians to limit their use of laser surgical apparatus because of the problems in properly controlling the path of the laser beam in and around the surgical site.
A laser beam has sufficient energy to heat a tool up to such high levels that it is hot to the touch, and thus is difficult for the surgical personnel to handle and could also burn the patient, in fact, even warm instruments are objectionable because they cause moisture to be driven out of the tissue so that tissue tends to adhere to the instrument. Laser surgical pulses are, in some instances, powerful enough to cause metal instruments, for example stainless steel instruments, to glow and sometimes to deteriorate under the effect of the laser beam. This is quite clearly an undesired result, which would obviously discourage the surgeons from using laser surgical tools. If a surgical tool could be provided which would effectively absorb laser energy beams so that they would not impinge upon tissue outside the desired surgical site and dissipate the absorbed energy, one expects that the use of laser surgical tools would increase and that laser surgery could be more reliable.